1. OPUS : Online Positioning User Service http://www.ngs.noaa.gov/OPUS/ ngs.opus@noaa.gov

2. WHAT IS OPUS? On-line Positioning User Service Fast & easy access to the NSRS (National Spatial Reference System) for GPS users

3. Quick Link to OPUS from NGS Home Page www.ngs.noaa.gov

4. You’ve got mail! OPUS solution

5. How Does OPUS Compute Position? 3 single baselines computed 3 positions averaged — simple mean (equal weights) Differences between positions include any errors in CORS coordinates

6. FILE: corv0590.05o 000416827 1008 NOTE: Antenna offsets supplied by the user were zero. Coordinates 1008 returned will be for the antenna reference point (ARP). 1008 NGS OPUS SOLUTION REPORT ======================== USER: jeff.olsen@noaa.gov DATE: January 13, 2006 RINEX FILE: corv059f.05o TIME: 19:08:14 UTC SOFTWARE: page5 0601.10 master3.pl START: 2005/02/28 05:00:00 EPHEMERIS: igs13121.eph [precise] STOP: 2005/02/28 06:59:30 NAV FILE: brdc0590.05n OBS USED: 4228 / 4314 : 98% ANT NAME: ASH700936B_M NONE # FIXED AMB: 25 / 29 : 86% ARP HEIGHT: 0.0 OVERALL RMS: 0.013(m) REF FRAME: NAD_83(CORS96)(EPOCH:2002.0000) ITRF00 (EPOCH:2005.1596) X: -2498423.165(m) 0.018(m) -2498423.872(m) 0.018(m) Y: -3802822.048(m) 0.021(m) -3802820.836(m) 0.021(m) Z: 4454737.695(m) 0.024(m) 4454737.792(m) 0.024(m) LAT: 44 35 7.91054 0.002(m) 44 35 7.92698 0.002(m) E LON: 236 41 43.48129 0.014(m) 236 41 43.42434 0.014(m) W LON: 123 18 16.51871 0.014(m) 123 18 16.57566 0.014(m) EL HGT: 107.485(m) 0.034(m) 107.108(m) 0.034(m) ORTHO HGT: 130.010(m) 0.043(m) [Geoid03 NAVD88] UTM COORDINATES STATE PLANE COORDINATES UTM (Zone 10) SPC (3601 OR N) Northing (Y) [meters] 4936954.907 105971.557 Easting (X) [meters] 475821.322 2277335.385 Convergence [degrees] -0.21381402 -1.98897497 Point Scale 0.99960719 0.99994603 Combined Factor 0.99959034 0.99992918 US NATIONAL GRID DESIGNATOR: 10TDQ7582136955(NAD 83) BASE STATIONS USED PID DESIGNATION LATITUDE LONGITUDE DISTANCE(m) AH2489 NEWP NEWPORT CORS ARP N443506.072 W1240342.736 60138.7 AJ6959 CHZZ CAPE MEARS CORS ARP N452911.437 W1235841.187 113322.4 DH4503 P376 EOLARESVR_OR2004 CORS ARP N445628.313 W1230608.100 42648.2 NEAREST NGS PUBLISHED CONTROL POINT AH2486 CORVALLIS CORS ARP N443507.910 W1231816.519 0.0 OPUS Output - Standard

7. Distribution of Horizontal Offset from Accepted Values 0.8 cm N-S RMS 1.4 cm E-W RMS > 200 CORS 2 hours of data

8. How Can I Improve My Results? Consider observing a longer session Avoid conditions that perturb the GPS signal— unsettled weather, solar flares, multipath (nearby reflective surfaces) Data sets of at least four hours have been shown to produce more reliable results

9. HOW IS THE ANTENNA HEIGHT MEASURED? ARP MARK The height is measured vertically (NOT the slant height) from the mark to the ARP of the antenna. The height is measured in meters. The ARP is almost always the center of the bottom-most, permanently attached, surface of the antenna. See GPS Antenna Calibration for photo’s and diagrams that show where the ARP is on most antennas: http://www.ngs.noaa.gov/ANTCAL / If the default height of 0.0000 is entered, OPUS will return the position of the ARP.

10. WHY DO I NEED THE ANTENNA TYPE? The antenna phase centers are located somewhere around here. The Antenna Reference Point (ARP) is almost always located in the center of the bottom surface of the antenna. The antenna offsets are the distance between the phase centers and the ARP You do not need to know these offsets. They are passed to the processing software through the antenna type Incorrect or missing antenna type  big vertical errors ARP phase ctr.

11. How do I get help? Study the Guidelines under “Using OPUS” Submit specific questions, comments or suggestions using “Contact OPUS” link Study the answers under “FAQs”

12. Areas Covered by OPUS

13. Recent Solutions

14. Files processed, 2002-2005

15. OPUS –$$$ receiver, hours of data, no archive OPUS Rapid Static minutes –$$$ receiver, minutes of data, no archive OPUS GIS –¢¢ receiver –¢¢ receiver, minutes of data, no archive OPUS-DB archive results –$$$ receiver, hours of data, archive results OPUS Projects –Multiple –Multiple $$$ receivers, archive results Many Flavors of OPUS Planned

16. NGS-modeled antenna GPS data OPUS website http://geodesy.noaa.gov/OPUS http://geodesy.noaa.gov/OPUS your datasheet QA/QC OPUS Concept observation notes control station photo * control station description * control station monument NGS-modeled antenna GPS data ( 4+hours ) OPUS website http://geodesy.noaa.gov/OPUS http://geodesy.noaa.gov/OPUS for registered users public datasheet QA/QC 2 reviews OPUS  Datasheet Concept observation notes * optional for “existing” stations.